let GX be non empty TopSpace; :: thesis: for A, B being Subset of GX st A is connected & B is connected & A meets B holds
( A \/ B c= Component_of A & A \/ B c= Component_of B & A c= Component_of B & B c= Component_of A )

let A, B be Subset of GX; :: thesis: ( A is connected & B is connected & A meets B implies ( A \/ B c= Component_of A & A \/ B c= Component_of B & A c= Component_of B & B c= Component_of A ) )
A1: ( A c= A \/ B & B c= A \/ B ) by XBOOLE_1:7;
A2: for C, D being Subset of GX st C is connected & D is connected & C /\ D <> {} holds
C \/ D c= Component_of C
proof end;
assume ( A is connected & B is connected & A /\ B <> {} ) ; :: according to XBOOLE_0:def 7 :: thesis: ( A \/ B c= Component_of A & A \/ B c= Component_of B & A c= Component_of B & B c= Component_of A )
then ( A \/ B c= Component_of A & A \/ B c= Component_of B ) by A2;
hence ( A \/ B c= Component_of A & A \/ B c= Component_of B & A c= Component_of B & B c= Component_of A ) by A1, XBOOLE_1:1; :: thesis: verum